1. FIELD OF THE INVENTION
The present invention relates to a gas-insulated switchgear apparatus (hereinafter referred to as "GIS"), or more in particular to a configuration of GIS suitable for power-receiving equipment.
2. DESCRIPTION OF THE PRIOR ART
A conventional two-channel lead-in two-bank GIS for power receiving is introduced, for example, in "Electric Railways" Vol. 39, No. 9, dated Sept. 1985, at page 16, FIG. 4, and is shown in FIG. 1 accompanying this specification. In this skelton diagram, the apparatus has an aligned-panel configuration comprising power-receiving units A, E including devices on the lead-in wire side arranged in one box-like case containing a low-pressure insulating gas sealed therein for each channel, units B, D on the lead-out side including devices connected with a transformer which are contained in one box-like case having a low-pressure insulating gas sealed therein, and a unit C with a wattage-metering instrument (hereinafter referred to as "MOF") involved contained in a single box-like case.
A conventional GIS having this circuit configuration comprises the power-receiving units A, E on the outermost side, the lead-out units B, D at inwardly adjacent positions thereto, and the MOF unit C at the central part in an aligned configuration.
The aforementioned configuration is also called a cubicle-type GIS generally. Among these devices, all the devices of the power-receiving units A, E and the lead-out units B, D are arranged in a gas-segmented box-like case as disclosed in JP-A-57-202805 and JP-A-59-106809 as well known. For the power-receiving units A, E, in particular, the above-cited reference in its Table 1 at page 18, Japanese Utility Model Laid-Open No. 9714/84 and Japanese Utility Model Laid-Open No. 107513/84, disclose a configuration in which only circuit breakers such as a vacuum circuit breaker or a gas circuit breaker are arranged in the air section outside of the gas segments of the box-like case. Bushings and cable heads are used as insulation lead means for these units. Also, the MOF unit C includes an oil-filled or gas-insulated MOF 1 used in the box-like case, and is connected with the other units A, B, D and E.
In the conventional aligned configuration in which the power-receiving units A and E are disposed on both sides with the lead-out units positioned inwardly thereof, however, the buses 10 and 11 for connecting these two types of units are required to be extended through the MOF C. Further, the buses 10, 11 are required to be connected with the MOF 1 by a bus 12, resulting in a large volume of the box-like case for sealing the insulating gas of the respective units. Also, the lead-in system on the power-receiving side generally includes a bushing or cable. The above-mentioned conventional GIS uses the former system, in view of the fact that the latter system, inspite of its advantages, leads to a problem of a larger floor space required.